i(t) = R(t)∫[0,∞)i(t-τ)g(τ)dτ
12 Dr. Hiroshi Nishiura is one of the few professionals of mathematical models of infectious diseases in Japan, and it is well known that his ability is outstanding. However, many people don't understand mathematical models themselves (I must confess that I can't say that I understand all of the findings because I'm not a professional of mathematical models either), so his findings and comments are easily deified. Because the contents of the mathematical model are a complete black box to many people, it makes it seem like the oracle is coming out like a shrine's oracle. Much of Japan's infection control policy relies on the Nishiura theory. So there is nothing wrong with that, but one of the problems in Japan is that there is no plan B in case plan A goes bust. Dr. Nishiura is an excellent scholar. It is not God. Hence the need to have that Plan B with the possibility of making a mistake. I am greatly concerned that bureaucrats and politicians who are prone to infallibilism will mistake science for an oracle. It is only when falsifiability is assured that science can continue to be scientific.
Mathematical models are the product of deductive methods. The deductive method is complemented by the inductive or abduction method, which is the basis of scholarship and the common sense of clinical medicine. It's a common occurrence in this industry that no matter how deducibly correct it may seem, it's actually not true. Even a huge intellect like Hegel or Marx can make a mistake by deduction alone.
I'm not saying don't use the model at all. I myself write a paper using a model. However, the model is not infallible, there are assumptions that are assumptions, and the assumptions are often wrong. Making use of Gram's stain means having full knowledge of what Gram's stain cannot do and does not understand, and Gram's stain cannot be used by Gram's stain universalists. It's the same thing. Mathematical models are also utilized in the UK, which is why Brits are very sceptical of their conclusions, and there are always counter-arguments and objections. It is a sound and scientific attitude.
15 Japan's "now" is a well-controlled state of infection, which is much better than Wuhan at its worst, or Italy, Spain, France, England, or New York at the present time. The problem is that it doesn't guarantee that it will "always work".
It is Tokyo that is of concern. The increase in reports of infection is not the only problem. The problem is that more and more infected people are unable to form clusters and cannot be traced. And the number of tests is much lower than that number of positive cases; it's too little that they only tested less than 100 people (the date of testing for the positives is unknown, but it's probably around here) to capture 47 infected people.
Again, it's not necessary to figure out all the infected people. However, it is troubling that the flow of infection, movement and clusters are out of sight. Therefore, the threshold for testing must be lowered in Tokyo. The threshold for testing varies with the circumstances. That's what I explained with the Korean example. Sticking to the Ministry of Health, Labour and Welfare's "standards" will lead to a misunderstanding of the phenomenon itself. Already in the Kansai region, infected people have been found with taste and smell abnormalities, and clusters have been detected from there. I would like to make more use of the athletic sensibilities of these clinicians. I'm not sure "where" in Tokyo is the barrier to lowering the number of inspections, but that barrier needs to be removed immediately.
17 This conceptual diagram that everyone is looking at - lowering the peak of the infection and shifting it to the side. This is all a product of deduction, and I don't know if it's really true. As mentioned above, the UK estimates already suggest that this is not enough. It is possible that the damage that was shifted to the side could simply be "extra-long damage".
And this is the key point: the idea of lowering the peak should not become the notion that the peak must be lowered, or the belief that the peak must be lowered, or the self-implication that the peak is not happening. In a pattern of Japanese failure to stick to Plan A, Diamond Princess allowed no-guard disembarkation by changing "secondary infection should not occur" to "it can't have happened". We need to keep our eyes on reality so that "peak shouldn't happen" doesn't become "I don't want to see a peak. Even if it is an inconvenient truth that we don't want to see.
19 Repeatedly. It's common knowledge in this industry that deductive methods are complemented by inductive methods. Nevertheless, PCR is often false-negative and has little power to determine the status of infection. That's why "testing everything" is so wrong. However, a serum test measuring immunoglobulin IgM and IgG would provide a more accurate picture of the "status of infection in the population. This, however, is not infallible. It is difficult to use for individual cases because it misses early infection, which is why it misses early HIV infection.Whether antibody testing is useful in individual cases remains to be tested, but it is well suited for epidemiological studies on a population basis. Roughly speaking, we can confirm whether the "infection is rampant" in Tokyo right now, or whether it's just an unfounded fear.
As a precedent, serology tests in London showed that the 2009 pandemic flu was 10 times more likely than previously predicted. Antibody testing is often performed after an outbreak, but now is a good time to examine COVID-19, which is becoming a chronic pandemic.
The UK is even more aggressive. The idea is to test for antibodies at home, and if they are found to be infected, they will use it as a basis for self-isolation at home. That strategy is flawed because with the lockdown in place, a negative test does not mean "no self-sequestration". However, the idea is that we want to control the infection as a whole, and I think it is worth considering.
Inductive legal confirmation of how many infections are occurring in Tokyo is necessary and useful. I'm not a prophet, so I don't know what the outcome will be.However, no matter what the outcome, scientists need to accept it and not hesitate to change their thesis and move on to Plan B in some cases. Scientists have to be coherent in their inconsistencies.They may not be coherent in form, but they must be coherent in principles and professionalism. Good faith in the facts.
1 Most of what I'm about to write is no different from what I've said and done in the past. However, I have been asked the same question repeatedly, so I would like to reiterate it. We have received many inquiries from overseas as well, so we should have prepared the same content in English, but due to time constraints, I'm afraid I'll have to skip it. This article is designed to be read without basic knowledge of infectious diseases and jargon, but it is rather difficult to understand. Please forgive me for that.
2 The fact that the number of COVID-19 reports in Japan is very low compared to other countries is attracting attention from home and abroad. Is it true? It has been pointed out that the number of tests is so small that we may be misreading the actual number of infected people.
3 However, this point is wrong at various layers. In the first place, Japan does not aim to capture all the numbers of COVID-19. Whether it's administrative testing or insured care, the state basically has a testing strategy in mind to diagnose, hospitalize, and isolate critically ill patients who need to be hospitalized. It is natural that they "haven't figured it out" and they don't intend to. That's not a bad thing.In fact, the situation is the same in every country, large or small, and no country, whether in the United States, Europe, or Asia, is aiming to "capture the whole number.
The WHO is not asking for such a thing. But instead, Japan gives PCR to asymptomatic returnees and isolates asymptomatic test-positive people in hospital (wasn't it home for people with minor illnesses?). It has not been coherent in its principles. So, people get anxious because "we're not sure what they want to do". It's a failure in the press.
4 The difference between Korea and Japan is the "result" and not the "purpose". In South Korea, where the number of infected people had surged in one place, we had to focus on inspections in and around the area. If such a phenomenon (let's call it an overshoot) occurs in Japan, the number of inspections will increase. When the situation is different, arguing only on the basis of the number of tests without observing the situation is like trying to say, "That team made 50 sliding tackles while this team made only one," without watching a football game. In games where you don't have to slide (e.g., when you're in possession the whole time), even 0 times isn't a "mistake," and of course 50 times isn't a mistake.
There are many diseases for which the total number of patients is not known. In Japan, we do not have a "total" number of influenza cases, but only a fixed-point observation. Because that's enough information, both epidemiologically and in terms of infection control. There is no accurate data on how many cases of the common cold occur each year in Japan. It's also a mistake to say that you can tell by looking at the receipt data, because many cold patients (like me) don't see a doctor and wait until they are cured naturally. Not only in medicine, but also in economics and political science, data are mostly based on sampling to estimate population numbers, and "whole numbers" is an inefficient way of grasping the situation.
6 We have not seen the devastation in Japan as in Italy, Spain or New York City. There is no medical collapse in a critically ill patient, no use of the operating room as an ICU, no piling up of bodies on a skating rink with no place to put them. Even if the "numbers" are not known, it is a fact that the current situation in Japan (including Tokyo) is much better controlled than in other countries.
7 Even so, you may be interested in "Well, what about the actual situation? There are estimates. For example, Dr. Hiroshi Nishiura and his group estimate that the number of mild illnesses in Japan may be twice the reported number. The catch rate is 0.44, with a 95% confidence interval of 0.37-0.50.
8 Although the study was based on data from China, there is no guarantee that the Chinese COVID-19 demographic is the same as the Japanese one. Also, since the original study did not include asymptomatic patients or those with minor illnesses that did not require hospitalization, the number of infected patients estimated on that basis would inevitably be an underestimate. If you are more paranoid, it's not unreasonable to believe that "the Japanese and Chinese viruses are different because of the mutation" (although I don't think so).
9 This does not diminish the value of the paper itself. The model must always use existing parameters, and it is often impossible to prove the external validity of these parameters. If the underlying parameters are not reasonable, the predictions will not be correct. A model assumes a simplified world insofar as it is a model. A model without simplification, which is an adjectival contradiction.
To complain about these "assumptions" of the mathematical model is like complaining, for example, "You can't explain disease B," when a randomized controlled trial is conducted for disease A. This is a meaningless tirade against the honor of the industry.
A mathematical model that assumes a certain hypothesis should have internal academic validity, but it is the responsibility of the reader, as a resident of the real world, to appraise it in the real world.
Just as the RCT findings for disease A should not be used for disease B, it is natural to understand the limitations of the mathematical model and to be careful when applying it to the real world. For example, it would be wrong to read the paper and conclude that the total number of infected people in Tokyo is about 500 as of March 26.
11 People make mistakes. The models are also wrong. Being wrong is not a big deal. The problem is to notice your mistakes and make corrections. Already, a group at Imperial College London has admitted that its original estimate that the peak of the infection should be moderated was "wrong" and has revised its prediction that the ICU will soon fail if it does not fight the virus fairly aggressively.